As Kage they all at base level have: High intel, high chakra control/reserves, high deducing skills, lots of control over the chakra natures, and so on. It's shared by all of them and while others do excel in certain parts more than others it's still not enough for me to put it as a + for their power overall.

Based on who I like most:1] Minato2] Hashirama3] Kakashi4] Tobirama5] Naruto6] Sarutobi7] Tsunade

Also Madara is the best Kage.I’m referring to Rinne Tensei Madara Uchiha with the Eternal Mangekyou Sharingan and Rinnegan doujutsus (with the rikidou paths ability) equipped with his Gunbai and control of the juubi and Gedou Mazou, a complete Susano’o, with Hashirama Senju’s DNA implanted in his chest so he can perform Mokuton kekkei genkai and yin-yang release ninjutsu as well as being extremely skilled in taijutsu and bukijutsu.

I believe that it would be a very bad idea for the bijū to have any recollection of its previous containers. It just spells for meta-gaming disaster, especially if the two competing souls do not like each other.

It's just a cheap, easy way out to gain information without doing actual IC work.

"I have to say a lot of people have been asking this question. No, really. A lot of people come up to me and they ask me. They say, "What's 2+2"? And I tell them look, we know what 2+2 is. We've had almost eight years of the worst kind of math you can imagine. Oh my god, I can't believe it. Addition and subtraction of the 1s the 2s and the 3s. Its terrible. Its just terrible. Look, if you want to know what 2+2 is, do you want to know what 2+2 is? I'll tell you. First of all the number 2, by the way I love the number 2. It's probably my favorite number, no it is my favorite number. You know what, it's probably more like the number two but with a lot of zeros behind it. A lot. If I'm being honest, I mean, if I'm being honest. I like a lot of zeros. Except for Marco Rubio, now he's a zero that I don't like. Though, I probably shouldn't say that. He's a nice guy but he's like, "10101000101", on and on, like that. He's like a computer! You know what I mean? He's like a computer. I don't know. I mean, you know. So, we have all these numbers and we can add them and subtract them and add them. TIMES them even. Did you know that? We can times them OR divide them, they don't tell you that, and I'll tell you, no one is better at the order of operations than me. You wouldn't believe it. That I can tell you. So, we're gonna be the best on 2+2, believe me. OK? Alright. Thank you."